Method and device for producing and filling containers made of thermoplastic plastic and containers produced in such a way

ABSTRACT

The invention relates to a method for producing and filling containers ( 1 ) made of thermoplastic plastic, in which an extruded plastic hose is inserted into an open mold having movable mold parts, mold parts forming the container ( 1 ) are closed, the hose being expanded by a pressure gradient acting on the hose in order to form the container ( 1 ), preferably in the form of a bellows, and being filled with filling material, and the level of the filling material is raised by reducing container volume in the direction of the container opening, a container closure ( 5 ) for the container opening being formed from the hose by closing head jaws of the mold, wherein said method is characterized in that the container ( 1 ), preferably in the region of the container closure ( 5 ), is formed in such a way that at least one section of the plastic hose remains unclosed for the time being in order to form a venting cannula ( 3 ) and in that, when the container volume is reduced, the level of the filling material is raised in such a way that at least air is displaced from the container ( 1 ) through venting cannula ( 3 ), and the venting cannula ( 3 ) is closed by closing the head jaws or by auxiliary head jaws.

The invention relates to a method for producing and filling containersmade of thermoplastic plastic, in which an extruded plastic tube isinserted into an open mold having movable mold parts, the mold partsforming the container are closed, wherein the tube is expanded by apressure gradient, acting on said tube, to the container, preferably inthe form of a bellows, and is filled with a filling material, and thelevel of the filling material is raised by displacing the containervolume in the direction of the container opening, wherein a containerclosure for the container opening is formed from the tube by closing thehead jaws of the mold. Furthermore, the invention relates to a devicefor carrying out the method and to a container that is produced in sucha way.

Methods of this type, such as the bottelpack® system, are widely used toproduce containers of various shapes, sizes, and for different purposes.In this case, they can also be co-extruded containers. In particular,they can be transparent, flexible containers made of polyethylene orpolypropylene. In many cases, the containers are both produced and alsofilled with a sterile filling material, such as pharmaceuticals, andsealed in an aseptic operation in one working step. Such a method isdisclosed in document WO 2009/086864 A1.

When such containers are used in medicine, it is essential for theperformance characteristics that the filling material can be removed ina suitable manner. If the filling material is, for example, a liquidthat is to be infused, for example, an anesthetic, then it must beensured that the container contains only a minimal residual volume ofair, so that when the liquid is squeezed out by squeezing the flexiblecontainer, a highly accurate dosage of the liquid is delivered.

With respect to these requirements, the object of the present inventionis to provide a method for producing containers which can be filled,with almost no air, in an economical and efficient way.

The invention achieves this object by means of a method having thefeatures specified in claim 1 in its entirety.

Accordingly, one essential feature of the invention lies in the factthat the procedure for molding the container closure from the plastictube is carried out in such a way that one section of the plastic tuberemains unclosed and that a venting cannula is formed. In the same or inan additional displacement step, in which the level of the fillingmaterial is raised as required, the residual volume of air is displacedat this point from the container through the venting cannula; andthereafter the venting cannula and, with it, the container are closed byclosing the head jaws or the auxiliary head jaws of the mold. When theliquid level is raised in this way, essentially no air or only a smallvolume of air remains inside the container after the venting cannula hasbeen closed. Then the venting cannula itself or sections thereof can beremoved along with the rest of the scraps. In one particular embodiment,the level could also be raised further or could be raised until theliquid is displaced through the respective venting cannula to theexterior; this would then result in a container having contents that aretotally free of air.

If the venting cannula is formed at the upper end of the containerclosure, then any relevant residual volume of air can be removed withouthaving to displace the contents as far as into the venting cannula.

Preferably, the venting cannula is closed directly at the wall of thecontainer closure by means of the auxiliary head jaws, so that theventing cannula can be severed directly at the container closure; and,as a result, a larger, protruding remaining portion of the cannula doesnot remain at the container closure. This approach makes it possible toproceed in such an advantageous way that the venting cannula is not onlyclosed by means of the auxiliary head jaws, but at the same time is alsosevered at the closing point or the welding spot. The auxiliary headjaws close the venting channel and, thus, create a thin section in thematerial, adjoining the container closure, by means of the cuttingedges, so that there is also the possibility of removing with ease theso-called head flash together with the former venting channel in astamping operation that takes place after the demolding process.

Preferably, the venting cannula is formed from a section of the plastictube that is located outside the central region of the containerclosure. This arrangement allows, in an advantageous way, the centralregion of the container closure to remain without an attachment point orwelding spot of the venting cannula, so that the applicability of thecontainer closure as an infusion connecting head is not adverselyaffected.

The subject matter of the invention is also, according to claim 7, adevice for carrying out the method. This device has movable mold partsfor forming a container from an extruded plastic tube. In this case, theclosing surfaces of the main head jaws of the mold that form thecontainer closure have recesses that leave a section of the plastic tubeunclosed in order to form a venting cannula; and the auxiliary headjaws, which can be moved relative to the main head jaws, can be movedinto an active position that closes the venting cannula.

At the same time, the arrangement is configured preferably in such a waythat the auxiliary head jaws are integrated into the main head jaws insuch a way that these auxiliary head jaws, which penetrate the recesses,can be moved into the active position in the direction of the closingmotions of the main head jaws.

The auxiliary head jaws can be moved in an especially advantageous wayby means of working cylinders, which are located in the main head jawsand can be actuated by means of pressurizing media. In addition or as analternative, it is also possible for servo motors to replace the saidworking cylinders.

Furthermore, the subject matter of the invention is also, according toclaim 10, an air-free container, which is produced according to theinventive method by means of the device according to the invention; andsaid container has a closed attachment point of a severed ventingcannula.

The invention is explained in detail below with reference to thedrawings. Referring to the drawings:

FIG. 1 is a side view of one embodiment of a container that is drawnslightly smaller in size compared to a practical embodiment, with thiscontainer being produced according to the invention in the form of abellows, which can be axially pressed together, before the ventingcannula has been severed;

FIG. 2 is a perspective oblique view of the container that is scaleddown compared to the container shown in FIG. 1;

FIG. 3 is an oblique view of the container that corresponds to the onein FIG. 2, after the venting cannula has been severed;

FIG. 4 is a simplified drawing in schematic form of a partially closedblow mold with the container formed therein, wherein the operating stateof filling the container with filling material is shown, and the headjaws of the mold that form the container closure are shown in the openposition;

FIG. 5 is a simplified top view in schematic form of the container fromFIG. 4, where only the open head jaws of the mold parts are visible;

FIG. 6 is a view similar to the one in FIG. 4, but the fill level of thefilling material is raised in a first displacement step;

FIG. 7 is a top view that corresponds to the view in FIG. 5 of thecontainer from FIG. 6;

FIG. 8 is a view similar to the one in FIG. 6, but the head jaws of themold are closed, so that a container closure and a venting cannula areformed from the plastic tube;

FIG. 9 is a top view of FIG. 8, but drawn to a larger scale;

FIG. 10 is a view similar to the one in FIG. 8, but the fill level ofthe filling material is raised further in a second displacement step;

FIG. 11 is a top view of FIG. 10 that corresponds to the view in FIG. 9;

FIG. 12 is a view similar to the one in FIG. 10, where the auxiliaryhead jaws are shown closed; and the venting cannula is closed andsevered by means of said auxiliary head jaws, and

FIG. 13 is a top view of FIG. 12 that corresponds to the view in FIG. 11and shows the auxiliary head jaws in the closed position.

The invention is explained below by means of the example of a container1 that is configured as a bellows and that is shown in detail in FIGS. 1to 3. It is clear that the invention can also be used just asadvantageously for the production of containers with smooth walls. FIGS.1 and 2 show the container 1 in an unfinished state, in which it isremoved from a blow molding machine, so that the venting cannula 3 isnot closed and not severed from the container closure 5. FIG. 3 showsthe finished state, in which the venting cannula 3 has been severed fromthe container closure 5 at a welding spot or attachment point 7. It isclear from the drawing that the venting cannula 3 and, thus, theattachment point 7 are located at a point that is moved outside thecentral region of the container closure 5.

FIG. 1 shows that the bottom of the container 1 is not formed flat, butrather exhibits a convexity 9 toward the inside. When the liquid isdispensed from the container 1, it is possible to displace the liquidfrom the container 1 by squeezing the bellows, so that no residualvolume of liquid remains, because the convexity 9 forms a displacer bodythat compensates for the dead length that remains when the bellows ispressed completely together.

FIGS. 4 to 13 show the sequence of the method according to theinvention, which is carried out on the basis of the known bottelpack®system. In this context, FIGS. 4 and 5 show the container 1, which isformed from a plastic tube 13 in a blow mold 11, while filling saidcontainer with liquid filling material 15. In this case, the movablehead jaws 17 of the blow mold 11 are located in the open position, sothat the container closure has not been formed yet by these head jaws 17and, therefore, the container 1 is still open. FIGS. 6 and 7 show afirst displacement step, wherein a displacer plunger 19 displaces thecontainer volume starting from the direction of the bottom 21, so thatthe liquid level 23 of the filling material 15 rises to the mid-levelheight shown in FIG. 6. Once again, the head jaws 17 are located in theopen position, so that the top view in FIG. 7 corresponds to the topview from FIG. 5.

It is apparent from FIGS. 5 and 7 that the closing surfaces 24 of thehead jaws 17 have semi-cylindrical recesses 25 that face each other.When the head jaws 17 are moved toward each other, as illustrated by thearrows in FIG. 8 and, as a result, a container closure 5 is formed fromthe plastic tube 13 (see FIGS. 8 and 9), that section of the plastictube 13 that may be found in the recesses 25 remains unclosed, so thatthe venting cannula 3, shown in FIGS. 1 and 2, is formed. The recesses25 are located outside the central region of the head jaws 17 (see FIGS.5 and 7), so that the venting cannula 3 opens, as stated, eccentricallyon the container closure 5.

FIGS. 10 and 11 illustrate a state in which a second displacement stepis carried out by means of the displacer plunger 19 after the formationof the container closure 5 and the venting cannula 3 while the head jaws17 are still closed, so that the liquid level 23 rises as far as up tothe vicinity of the opening region of the venting cannula 3 inside thecontainer closure 5, while the air flows out of the container 1 throughthe venting cannula 3. As a result, the container 1 is practically freeof a residual air volume.

Having reached this state, the venting cannula 3 is closed, as shown inFIGS. 12 and 13. This closing is performed by means of the auxiliaryhead jaws 31, which are integrated into the head jaws 17. As shown withthe motion arrows 33 in FIGS. 12 and 13, these auxiliary head jaws canbe moved toward each other. The auxiliary head jaws 31 have weldingedges 35, which perform a closing and severing action at the ventingcannula 3, so that the venting cannula 3 is severed from the containerclosure 5 at the attachment point 7. The auxiliary head jaws 31 areactuated by means of actuating cylinders 37 (FIG. 13), which can beactuated by means of pressurized media.

1. A method for producing and filling containers (1) made of thermoplastic plastic, in which an extruded plastic tube (13) is inserted into an open mold (11) having movable mold parts, the mold parts forming the container (1) are closed, wherein the tube is expanded by a pressure gradient, acting on said tube, to the container (1), preferably in the form of a bellows, and is filled with a filling material (15), and the level (23) of the filling material (15) is raised by displacing the container volume in the direction of the container opening, wherein a container closure (5) for the container opening is formed from the tube (13) by closing the head jaws (17) of the mold (11), characterized in that the container (1), preferably in the region of the container closure (5), is formed in such a way that at least one section of the plastic tube (13) initially remains unclosed in order to form a venting cannula (3) and that, when the container volume is displaced, the level (23) of the filling material (15) is raised in such a way that at least the air is displaced from the container (1) through the venting cannula (3), and the respective venting cannula (3) is closed by closing the head jaws (17) or the auxiliary head jaws (31).
 2. The method according to claim 1, characterized in that the venting cannula (3) is formed in the region of the upper end of the container closure (5).
 3. The method according to claim 2, characterized in that the venting cannula (3) is closed directly at the exterior of the container closure (5) by means of the auxiliary head jaws (31).
 4. The method according to claim 3, characterized in that the venting cannula (3) is severed directly at the wall of the container closure (5) by means of the auxiliary head jaws (31).
 5. The method according to claim 1, characterized in that the venting cannula (3) is formed from a section of the plastic tube (13) that is located outside the central region of the container closure (5).
 6. The method according to claim 1, characterized in that the displacement of the container volume is carried out in such a way that a convexity (9) of the bottom (21) is produced, starting from the bottom (21) of the container into the interior of the container (1).
 7. A device for carrying out the method according to claim 1, comprising movable mold parts for forming a container (1) from an extruded plastic tube (13), characterized in that the closing surfaces (24) of the main head jaws (17) of the mold (11) that form the container closure (5) have recesses (25) that leave a section of the plastic tube (13) unclosed in order to form at least one venting cannula (3), and that the auxiliary head jaws (31), which can be moved relative to the main head jaws (17), can be moved into an active position closing the venting cannula (3).
 8. The device according to claim 7, characterized in that the auxiliary head jaws (31) are integrated into the main head jaws (17) in such a way that these auxiliary head jaws, which penetrate the recesses (25), can be moved into the active position in the direction of the closing motions of the main head jaws (17).
 9. The device according to claim 7, characterized in that the auxiliary head jaws (31) can be moved by means of working cylinders (37), which are located in the main head jaws (17) and can be actuated by means of pressurized media.
 10. An air-free container (1), which is produced according to the method according to claim 1, said container having a closed attachment point (7) of a severed venting cannula (3). 